The subject matter disclosed herein relates to turbines and, more particularly, to systems and devices for reducing disturbances and windage effects in a turbine.
Some power plant systems, for example certain nuclear, simple cycle and combined cycle power plant systems, employ turbines in their design and operation. Some of these turbines (e.g., steam turbines, gas turbines, etc.) include components which are exposed to a flow of working fluid during operation. As the working fluid flows through the turbine, features and/or interrupted surfaces on some components (e.g., apertures, counterbores, etc.) disrupt the working fluid creating drag and noise (i.e., windage effects) which reduce turbine efficiency and may increase the operating temperature of surrounding components. Some systems use jam nuts to fill counterbores which streamline component surfaces and thus reduce the effect these features have on the working fluid flow. During installation, bolts with extra threading are installed in counterbore holes of the turbine, this extra threading is machined to connect to and retain a complementary jam nut within the counterbore hole. Once the bolt is installed, the jam nut is threaded onto the end of the bolt via the extra threading such that the jam nut fills the counterbore opening, thereby reducing disturbances, heat-up, and power losses associated with the counterbore. However, these jam nuts may complicate turbine maintenance, require additional tooling, apply extra weight and stress to the bolts during operation, and must be anti-rotated, often by semi-permanent methods (staking).